[RFC 1/3] devlink: add flash update command

[Jakub Kicinski <jakub.kicinski@netronome.com>]

Add devlink flash update command. Advanced NICs have firmware
stored in flash and often cryptographically secured. Updating
that flash is handled by management firmware. Ethtool has a
flash update command which served us well, however, it has two
shortcomings:
 - it takes rtnl_lock unnecessarily - really flash update has
   nothing to do with networking, so using a networking device
   as a handle is suboptimal, which leads us to the second one:
 - it requires a functioning netdev - in case device enters an
   error state and can't spawn a netdev (e.g. communication
   with the device fails) there is no netdev to use as a handle
   for flashing.

Devlink already has the ability to report the firmware versions,
now with the ability to update the firmware/flash we will be
able to recover devices in bad state.

To enable easy interoperability with ethtool add the target
partition ID. We may or may not add a different method of
identification, but there is no such immediate need.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
---
 include/net/devlink.h        |  2 ++
 include/uapi/linux/devlink.h |  6 ++++++
 net/core/devlink.c           | 30 ++++++++++++++++++++++++++++++
 3 files changed, 38 insertions(+)

diff --git a/include/net/devlink.h b/include/net/devlink.h
index 07660fe4c0e3..55b3478b1291 100644
--- a/include/net/devlink.h
+++ b/include/net/devlink.h
@@ -529,6 +529,8 @@ struct devlink_ops {
 				      struct netlink_ext_ack *extack);
 	int (*info_get)(struct devlink *devlink, struct devlink_info_req *req,
 			struct netlink_ext_ack *extack);
+	int (*flash_update)(struct devlink *devlink, const char *path,
+			    u32 target, struct netlink_ext_ack *extack);
 };
 
 static inline void *devlink_priv(struct devlink *devlink)
diff --git a/include/uapi/linux/devlink.h b/include/uapi/linux/devlink.h
index 72d9f7c89190..f4417283fd1b 100644
--- a/include/uapi/linux/devlink.h
+++ b/include/uapi/linux/devlink.h
@@ -103,6 +103,8 @@ enum devlink_command {
 	DEVLINK_CMD_HEALTH_REPORTER_DUMP_GET,
 	DEVLINK_CMD_HEALTH_REPORTER_DUMP_CLEAR,
 
+	DEVLINK_CMD_FLASH_UPDATE,
+
 	/* add new commands above here */
 	__DEVLINK_CMD_MAX,
 	DEVLINK_CMD_MAX = __DEVLINK_CMD_MAX - 1
@@ -326,6 +328,10 @@ enum devlink_attr {
 	DEVLINK_ATTR_HEALTH_REPORTER_DUMP_TS,		/* u64 */
 	DEVLINK_ATTR_HEALTH_REPORTER_GRACEFUL_PERIOD,	/* u64 */
 	DEVLINK_ATTR_HEALTH_REPORTER_AUTO_RECOVER,	/* u8 */
+
+	DEVLINK_ATTR_FLASH_UPDATE_FILE_NAME,	/* string */
+	DEVLINK_ATTR_FLASH_UPDATE_TARGET_ID,	/* u32 */
+
 	/* add new attributes above here, update the policy in devlink.c */
 
 	__DEVLINK_ATTR_MAX,
diff --git a/net/core/devlink.c b/net/core/devlink.c
index 46c468a1f3dc..a4b5e194e33e 100644
--- a/net/core/devlink.c
+++ b/net/core/devlink.c
@@ -2660,6 +2660,27 @@ static int devlink_nl_cmd_reload(struct sk_buff *skb, struct genl_info *info)
 	return devlink->ops->reload(devlink, info->extack);
 }
 
+static int devlink_nl_cmd_flash_update(struct sk_buff *skb,
+				       struct genl_info *info)
+{
+	struct devlink *devlink = info->user_ptr[0];
+	const char *file_name;
+	u32 target = 0;
+
+	if (!devlink->ops->flash_update)
+		return -EOPNOTSUPP;
+
+	if (!info->attrs[DEVLINK_ATTR_FLASH_UPDATE_FILE_NAME])
+		return -EINVAL;
+	file_name = nla_data(info->attrs[DEVLINK_ATTR_FLASH_UPDATE_FILE_NAME]);
+
+	if (info->attrs[DEVLINK_ATTR_FLASH_UPDATE_TARGET_ID])
+		target = nla_get_u32(info->attrs[DEVLINK_ATTR_FLASH_UPDATE_TARGET_ID]);
+
+	return devlink->ops->flash_update(devlink, file_name, target,
+					  info->extack);
+}
+
 static const struct devlink_param devlink_param_generic[] = {
 	{
 		.id = DEVLINK_PARAM_GENERIC_ID_INT_ERR_RESET,
@@ -4876,6 +4897,8 @@ static const struct nla_policy devlink_nl_policy[DEVLINK_ATTR_MAX + 1] = {
 	[DEVLINK_ATTR_HEALTH_REPORTER_NAME] = { .type = NLA_NUL_STRING },
 	[DEVLINK_ATTR_HEALTH_REPORTER_GRACEFUL_PERIOD] = { .type = NLA_U64 },
 	[DEVLINK_ATTR_HEALTH_REPORTER_AUTO_RECOVER] = { .type = NLA_U8 },
+	[DEVLINK_ATTR_FLASH_UPDATE_FILE_NAME] = { .type = NLA_NUL_STRING },
+	[DEVLINK_ATTR_FLASH_UPDATE_TARGET_ID] = { .type = NLA_U32 },
 };
 
 static const struct genl_ops devlink_nl_ops[] = {
@@ -5164,6 +5187,13 @@ static const struct genl_ops devlink_nl_ops[] = {
 		.internal_flags = DEVLINK_NL_FLAG_NEED_DEVLINK |
 				  DEVLINK_NL_FLAG_NO_LOCK,
 	},
+	{
+		.cmd = DEVLINK_CMD_FLASH_UPDATE,
+		.doit = devlink_nl_cmd_flash_update,
+		.policy = devlink_nl_policy,
+		.flags = GENL_ADMIN_PERM,
+		.internal_flags = DEVLINK_NL_FLAG_NEED_DEVLINK,
+	},
 };
 
 static struct genl_family devlink_nl_family __ro_after_init = {
-- 
2.19.2